Banter, chit-chat, gossip, natter, tête-a-tête: these are just a few of the terms for the varied ways in which we interact with one another through conversation. We take informal conversation for granted because it's so natural and everyday; but if we analyse it we can discover surprising features. The spectacular linguistics prof explores some of the findings he reports in his latest book, Let's Talk: How English Conversation Works, from the first recorded instances a thousand years ago to the latest trends taking place online.